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Methods: MC/MSC co-culture was used to examine MC effects on MSC proliferation and differentiation. MC granulate (MCG) was then used to further examine the mechanisms by which MCs exerted their effects on MSC proliferation, migration, and myogenic differentiation. The effects of MCs on MSC activity in vivo was evaluated by immunohistological analysis on MC- and saline-treated infarcted mouse hearts at 3 and 7 days post-MI

Conclusions: MSCs can oscillate between proliferative and differentiated states. MCs promote proliferation at the expense of differentiation early after MI through PDGFR, downregulation of miR-145 and -143, and the Klf4-myocardin signalling axis to promote MSC accumulation. This in turn results in a larger cardiac MSC pool for later myofibroblast differentiation, facilitating improved wound healing.